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Discussion Starter · #1 ·
looking for advice on shortening the barrel on my pre-ban.

i want to shorten and replace a permanent flash-hider
to make an OAL 16.5" bbl.

the "shortening" will affect the gas-operation, so....

could i get away with just enlarging the gas port hole?

if so, any recommendations on hole size? something
along the lines of a 13" ac556 hole?

i've never monkeyed with the gas housing on a mini.
any real caveats or troubles to expect? any source of
grand knowledge?

thanks.
 

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Welcome aboard,sorry I cant answer that question, but Im sure some of the guys on here can.


Once again welcome aboard!!!
 

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Welcome mordecai, you came to the right place for knowledge on the mini-14. The shortening the barrel will not affect the gas operation, other than a velocity loss of 31 to 58 fps per inch. Some have gotten better accuracy after cutting off some of the barrel. Most of us have gotten better accuracy without cutting the barrel. The important thing is a square cut, and to "recrown" the muzzle. Here is a 2 page thread you can read up on: http://www.perfectunion.com/forums/showthr...15&pagenumber=1
As far as the gas operation is concerened we find the factory gas bushing is too large, so many of us have installed a smaller one which greatly reduces recoil.
Here is another excellent thread from zman who has documented the effects of shortening the mini's barrel. I hope this is of help to you. Again welcome. Keep us posted on how it turns out.
 

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Isn`t the Mini14 barrel 18" stock??? In order to get a 16.5" total length barrel with flash-hider, the barrel is going to have to be cut back to 13" +/- . The .223 suffers greatly in a short barrel and much more than 50fps per inch., remember that figure comes from a full barrel being cut back.....starting at 20-24" then removing an inch at a time. You will suffer serious loss of fps. To gain what ? An inch and a half less barrel length, not to mention some serious muzzle blast and flash.......very serious. Chop if you like, but don`t see the reasoning. Regards LTS
 

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Discussion Starter · #5 ·
Oh yea - it's all about the blast. HAHA

Just want something different. It's not like
the accurracy is going to suffer greatly.

The .223's energy is lost considerably, like
you said, from a non-progressive, short barrel,
but it's for plinking, nothing else.
 

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Liktoshoot you are correct, the velocity loss is nearer 150 fps per inch, as documented by Z-man's accuracy stickey post. The 38 to 50 fps came from my chrony for increase in velocity of 1/2 grn of powder on some loads I've been working on. My brain must have skiped a beat. Thanks for the correction.
 

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I think Mordecai has the right idea, and I plan to do the same thing to my Mini-14 in the near future.

Most AR-15 flash hiders (military, Vortex, Phantom, etc.) will provide at least 16" of barrel length if permanently attached to a 14.5" barrel. The U.S. military seems to be moving towards a 14.5" barrel with the M4 M16 variant -- I've read that this barrel length represents a good compromise between better handling vs. loss of velocity.

I also think the increased accuracy associated with shortening the barrel of a Mini-14 a couple of inches (see DRC's web page documenting this, as posted at this forum quite a few times) more than makes up for the reduction in velocity.

Brad D.
 

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Shortening the barrel did have a noticable positive effect on accuracy in my tests. It offerered about a .5" improvement in group size over the stock barrel with a muzzle brake.

The muzzle blast and flash are definitely more pronounced with the shorter barrel. Also, the muzzle velocity did drop - 1.25" of barrel removed cost roughly 185 fps.

I looked at my tests like this...a Ruger replacment barrel is only about $65, so if I butchered the thing or shortening it had a negative effect, I wouldn't be out huge cash.

Fortunately, shortening the barrel turned out to be a good thing for my Mini.
 

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Discussion Starter · #9 ·
(Man - you guys respond - this is 10 times better than most boards!)

I still have a concern. I've chopped a few barrels in my time,
down to 16.5" and (being new and stoopid) found that cycling
reliability suffered.

Case in point, I have an ancient SKS I chopped and now needs
the gas-port hole enlarged to provide more gas to cycle the
action.

Why is this not the case with a Mini-14?

Already provides enough gas? Different type of gas-capture?

What's the story morning glory?
 

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Shortening the barrel had no effect on case feed or the ejection cycle whatsoever. The Mini's with stock gas bushings deliver sufficient pressure levels to cycle action and have enough left over to sling a spent case like it nobodys business.

Even with the smaller gas bushing I have installed, the gun has yet to fail to cycle, feed, or eject a case.
 

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If it doesn't improve accuracy how come members on this board have had improved groups after shortening their barrels?
 

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Barrel Length Fallacy 101:

Gun Range Fiction - Longer barrels are more accurate.

Physics Fact - Two identical, perfectly rigid bores will emit a projectile to the exact same points, regardless of the bore length.

The Real World Truth - A "perfectly rigid bore axis" is a lofty objective that, to my knowledge, no barrel maker has ever achieved. In fact, every barrel ever produced suffers to some measurable degree from pressure and heat, and exhibts those effects in the form of barrel harmonics and heat distortion.

--------------------------------------------------------

Now......back to the topic....let me just say that after shortening the barrel in measured increments, monitoring the before and after results at every stage, and then test firing approximately 200 recorded rounds from a machine rest in a temperature controlled indoor facility, I will tell you without any doubt, that the data I have shows otherwise:

Shortening the barrel decisively improved accuracy.

I have a complete test record for this firearm, including all chrono and load data, complete before/after documentation, and 25 years of gunsmithing for Uncle Sam to back up my statements.

If you don't think shortening can increase the rigidity or improve the accuracy of a thin, low-mass barrel...well, that's your opinion.

However, you sir, would be incorrect in your belief.
 

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LTS,

Cutting a barrel shorter can increase accuracy. A shorter barrel is stiffer and therefore theoretically more accurate. This is the case for all rifles, but it is probably especially true for the Mini-14 factory barrel since it is so thin and "whippy".

There also is another reason specific to Mini-14s for shortening the barrel. At DRC Custom Guns' web page (http://www.drccustomgunsights.com/), they state this about Mini-14s: "After cutting a large number of barrels down we found that the muzzle measured from .0002-.002 larger than it did 2 inches back. This is why the factory barrels are so erratic on accuracy." You can find this discussion at the "About Us And Our Services" section of their web page.

Thanks to Z-man's excellent posts above and previously on this forum, we have verification that DRC's claims are valid. If you have evidence to the contrary, please post it here.

Brad D.
 

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Maybe I should clairify this a little better. We are not talking about a custom barrel and certainly not a custom rifle....by any means. People confuse accuracy as opposed to real accuracy, or perceived accuracy. I have dissproved this many times and it`s really easy to do. What you are doing is shortening the full cycle of time......you are not accuarcy enhancing.......your foling yourself. I have test fired many rifles, then had the barrels shortened or replaced. I have used many different rifles and calibers. Removing the heat factor (consistant firing) to prevent walking or wondering zero. Since I build custom 10/22`s.....I`ll use it as one example.

Using the factory barrel and CCI Green target.

10 slow fire shots, with five minute (timed) intervals between each shot and one fouling shot from a clean barrel. 11 rounds total. Stock Ruger 10/22. 10 shots at 25 yards, one ragged hole, measuring just under 1/4"

Custom Ruger 10/22, I won`t go into eveything this one had, but I hand fit everything and the parts cost was over a thousand dollars.......less the receiver. Same size group, but fired from a 22" custom barrel.

Both of these rifles were fired from a rest with all human error removed, there by giving the pure rifle accuarcy. The device used for this removes all human factors, so the results are pure. No breathing, flinch, jerk......zip-nada. No physical contact is made with the rifle....none. I have done this for years with many different rifles and calibers. This is how I ring the best out of each rifle I build. That way there is no question of blaming the rifle. Best LTS

Sorry, veiw device here:

http://www.lahticompany.com/
 

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LTS,

You’re efforts to clarify things have me more confused. You said:

“People confuse accuracy as opposed to real accuracy, or perceived accuracy. I have dissproved this many times and it`s really easy to do. What you are doing is shortening the full cycle of time......you are not accuarcy enhancing.......your foling yourself. “

I don’t follow all of your post, but I can only assume that Zman or DRC tested the pre- and post-barrel shortening accuracy of their Mini-14s under similar conditions. Zman sounds like he knows what he’s talking about, and DRC has a good reputation in the gunsmithing world – I’m pretty sure we aren’t talking about “perceived” accuracy here. To me, the fact that DRC has reported the dimensional problems at the muzzle (as quoted in my previous post) is hard evidence that removing a couple of inches from the end of a Mini-14 can only improve accuracy if done correctly (square cut, etc.).

Then, you go on to make a comparison between two different rifles (a factory 10/22 and a custom 10/22) – again, I don’t follow your logic here, it sounds like you’re making an apples to oranges comparison. The previous posts above have all been referring to the same rifle tested before and after shortening the barrel, not different rifles.

Brad
 

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This is slightly warped logic twisted with fact. First you claim equally ridged barrels of different length`s will shoot to the same POA, then you claim....shortening will will improve accuracy. How can that be.....since equal rigidity...is, well, equal.

Now, harmonic`s is still yet another story, but being that the Mini`s barrel is "clamped down" harmonic`s go out the door, as the clamp negates harmonic`s.....because the barrel now is dampened to the stock.

In reality, what is happening is a form of "lock time" though this would be "barrel time." This micro shortening of the barrel is simply removing human error in this already famous and inherently in-accuarate rifle. Since most all Mini`s shoot an average of 4.25 MOA on their best days (everyone claims their`s is the exception......though I have never seen it proved on the firing line...Stock rifle) and even AI can only claim 1" MOA with big dollars and reloads on a good day.

Now as to barrel length, some barrels do improve with shortening.....but these fall with in the same parameters of bullet in the barrel time, but also from freefloating, bedding actions or barrel tuners. But again, this depends on just how thin the barrel is and it`s length. The facts are that thin barrels suffer more from heat walking or wondering, much more than shortening the barrel could ever improve accuaracy. Two-Shae......LTS
 

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1. "First you claim equally ridged barrels of different length`s will shoot to the same POA...";

then you ask...

"How can that be.....since equal rigidity...is, well, equal."



ANSWER

I'll offer it again:

*Physics Fact - Two identical, perfectly rigid bores will emit a projectile to the exact same points, regardless of the bore length. *


Remember, there is a huge difference between the words perfectly and equally, especially when dealing with a barrel.

Why? It should be getting obvious by now, but here goes...

If you start with two barrels that are the made of the same material, same stiffeness, inherent structual strength, identical in every way...and then cut one off...the shorter barrel will always be more rigid than the longer barrel.

To obtain two different barrels of equal rigidity but of different length, you will have to change the material or structural composition of at least one of the barrels...and then you are no longer comparing identical barrels.

Simple.




2. "...being that the Mini`s barrel is "clamped down" harmonic`s go out the door.."


ANSWER

Huh? You can't believe this can you? I hope not, because your statement is patently wrong.

((FYI: There is a good deal of data available on how such barrel contact can actually act as a fulcrum as exacerbate the effects of pressure waves and heat distortion at the muzzle. But that is beyond 99.9% of the needs for the Mini. Besides, this is the stuff I save for the .308 and the 1500+ Club.))



3. "Now as to barrel length, some barrels do improve with shortening..."


ANSWER

Glad to see you've finally changed your mind, LTS! Got the saw out yet? LOL !!!



Best to you, LTS...enjoy reading your stuff...you tell it like you see it, and I appreciate it at places like this.

The one thing we can all agree on is our passion for shooting and firearms. Everything else is just opinion...
 

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"Why? It should be getting obvious by now, but here goes...

If you start with two barrels that are the made of the same material, same stiffeness, inherent structual strength, identical in every way...and then cut one off...the shorter barrel will always be more rigid than the longer barrel."


Well.......... DUH???

That don`t make it more accuarate....just stiffer. Only barrel time has been reduced.

Clamping a barrel does not help harmonic`s, it actually creats two points of different origin for harmonic`s. One from the receiver to the clamp area and from the clamp area forward. Each one different in length and balance....thus creating an interruption of real physic`s. Easily proven by clamping a barrel blank to a table and striking it in two different areas. One at short length from the clamp and the other end further from the clamping area. Vibration is vibration......very simple physic`s......though some try to complicate it or create new science physic`s. Yer serve.....Duece. LTS
 
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